Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D135/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a carboxyl radical, and containing at least another carboxyl radical in the molecule, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Coating compositions based on derivatives of such polymers
  • C09D135/06—Copolymers with vinyl aromatic monomers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F212/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
  • C08F212/02—Monomers containing only one unsaturated aliphatic radical
  • C08F212/04—Monomers containing only one unsaturated aliphatic radical containing one ring
  • C08F212/06—Hydrocarbons
  • C08F212/08—Styrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F220/00—Copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride ester, amide, imide or nitrile thereof
  • C08F220/02—Monocarboxylic acids having less than ten carbon atoms; Derivatives thereof
  • C08F220/10—Esters
  • C08F220/12—Esters of monohydric alcohols or phenols
  • C08F220/16—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms
  • C08F220/18—Esters of monohydric alcohols or phenols of phenols or of alcohols containing two or more carbon atoms with acrylic or methacrylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F290/00—Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups
  • C08F290/02—Macromolecular compounds obtained by polymerising monomers on to polymers modified by introduction of aliphatic unsaturated end or side groups on to polymers modified by introduction of unsaturated end groups
  • C08F290/04—Polymers provided for in subclasses C08C or C08F
  • C08F290/046—Polymers of unsaturated carboxylic acids or derivatives thereof
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
  • C09B67/00—Influencing the physical, e.g. the dyeing or printing properties of dyestuffs without chemical reactions, e.g. by treating with solvents grinding or grinding assistants, coating of pigments or dyes; Process features in the making of dyestuff preparations; Dyestuff preparations of a special physical nature, e.g. tablets, films
  • C09B67/0071—Process features in the making of dyestuff preparations; Dehydrating agents; Dispersing agents; Dustfree compositions
  • C09B67/0084—Dispersions of dyes
  • C09B67/0085—Non common dispersing agents
  • C09B67/009—Non common dispersing agents polymeric dispersing agent
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/02—Printing inks
  • C09D11/03—Printing inks characterised by features other than the chemical nature of the binder
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/16—Writing inks
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/30—Inkjet printing inks
  • C09D11/32—Inkjet printing inks characterised by colouring agents
  • C09D11/324—Inkjet printing inks characterised by colouring agents containing carbon black
  • C09D11/326—Inkjet printing inks characterised by colouring agents containing carbon black characterised by the pigment dispersant
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D133/00—Coating compositions based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Coating compositions based on derivatives of such polymers
  • C09D133/04—Homopolymers or copolymers of esters
  • C09D133/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, the oxygen atom being present only as part of the carboxyl radical
  • C09D133/10—Homopolymers or copolymers of methacrylic acid esters
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D17/00—Pigment pastes, e.g. for mixing in paints
  • C09D17/001—Pigment pastes, e.g. for mixing in paints in aqueous medium
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
  • C09D5/02—Emulsion paints including aerosols
  • C09D5/024—Emulsion paints including aerosols characterised by the additives
  • C09D5/027—Dispersing agents
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
  • C09D7/40—Additives
  • C09D7/45—Anti-settling agents
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/087—Binders for toner particles
  • G03G9/08702—Binders for toner particles comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • G03G9/08706—Polymers of alkenyl-aromatic compounds
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/087—Binders for toner particles
  • G03G9/08702—Binders for toner particles comprising macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • G03G9/08706—Polymers of alkenyl-aromatic compounds
  • G03G9/08708—Copolymers of styrene
  • G03G9/08711—Copolymers of styrene with esters of acrylic or methacrylic acid
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
  • G03G9/00—Developers
  • G03G9/08—Developers with toner particles
  • G03G9/12—Developers with toner particles in liquid developer mixtures
  • G03G9/13—Developers with toner particles in liquid developer mixtures characterised by polymer components
  • G03G9/132—Developers with toner particles in liquid developer mixtures characterised by polymer components obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds

Definitions

• This invention relates to a novel copolymer, its use and the like, and more specifically, to a copolymer useful as a pigment dispersant or the like, use of the copolymer as a pigment dispersant, a pigment dispersion and its use, and the like.
• pigment dispersants and resin dispersions have been developed to date for various use, and their applications range across extremely diverse products.
• known products include those of the comb structure each obtainable by reacting a polyester of a carboxylic acid, which has a single terminal COOH group, with a polyamine (Patent Document 1); those each obtainable by reacting a solvent-soluble polymer and a compound having one or more functional groups as pigment-adsorbing groups with an isocyanate (Patent Document 2); and those each obtainable by subjecting styrene and an acrylic monomer to random copolymerization (Patent Document 3).
• resin dispersions there are water-based resin dispersions each obtainable by neutralizing an acrylic or acrylic styrene resin of low molecular weight to dissolve it in water, adding a monomer to the resulting system and then polymerizing them (Patent Document 4); and non-aqueous resin dispersions each obtainable by adding, in the presence of a macromonomer obtained by reacting glycidyl methacrylate, another radical polymerizable monomer to a methacrylate polymer containing at an end thereof a residual carboxyl group of a chain transfer agent such as mercaptoethylcarboxylic acid and having a long-chain hydrocarbon group of eight carbon atoms or a like number of carbon atoms soluble in an aliphatic hydrocarbon solvent (Patent Document 5).
• a macromonomer obtained by reacting glycidyl methacrylate, another radical polymerizable monomer to a methacrylate polymer containing at an end thereof a residual carboxyl group
• An object of the present invention is, therefore, to provide a copolymer useful as a pigment dispersant or the like capable of providing pigment dispersions useful in IJ inks, CF colors and other applications.
• R represents a hydrogen atom or an n-valent ester residual group
• n stands for a number of from 1 to 4
• Y represents a methacrylic polymer
• the copolymer D according to the present invention can further comprise (C) units of a monomer (which may hereinafter be simply called “units C”) other than the units (A) or the units (B).
• the units A may preferably comprise a copolymer of a compound represented by the below-described formula (2) and a methacrylic monomer.
• X represents a halogen atom, alkylthio group, arylthio group, alkylsulfoxide group, arylsulfoxide group, benzyloxy group or alkylbenzyloxy group
• R represents a hydrogen atom or an n-valent ester residual group
• n stands for a number of from 1 to 4.
• the monomer forming the units B may preferably be at least one of styrene, ⁇ -methylstyrene, vinyltoluene, vinyldimethylbenzene, vinylethylbenzene, and vinylnaphthalene; and the monomer forming the units C may preferably be a monomer having a group selected from the group consisting of a carboxyl group, a hydroxyl group, a sulfonic group, a phosphoric group, an amino group, a quaternary ammonium group, and nitrogen-containing heterocyclic groups.
• the units A in the copolymer D according to the present invention may each preferably contain acid groups neutralizable with an alkaline substance, and may each preferably have an acid value of from 50 to 300 mgKOH/g; the copolymer D may preferably be dispersed or emulsified in a liquid medium; and the acid groups may preferably be carboxyl groups, sulfonic groups and/or phosphoric groups.
• the present invention also provides a pigment dispersant comprising the copolymer D according to the present invention; a pigment dispersion comprising a pigment dispersed by the above-described pigment dispersant; and a paint, ink, coating formulation or toner comprising the above-described pigment dispersion as a colorant.
• the present inventors have pursued developments of novel pigment dispersants and resin dispersions capable of imparting high pigment dispersibility and high physical properties.
• the present invention has developed pigment dispersants and resin dispersions, which are polymers having novel structures and good performance over such conventional pigment dispersants and resin dispersions as described above. These copolymers are equipped with very good pigment dispersibility as pigment dispersants, and can provide microdispersions of pigments.
• the resulting articles can show improved performance, for example, high adhesion, high chromogenicity, high gloss, high heat resistance, and so on.
• the copolymer according to the present invention even when formulated into a resin dispersion, not only has storage stability but also remains stable without precipitation even when another solvent is mixed; and, when employed as a film-forming component, can afford a film having excellent physical properties such as high adhesion and high gloss.
• R represents a hydrogen atom or an n-valent ester residual group
• n stands for a number of from 1 to 4
• Y represents a methacrylic polymer
• the units A in the copolymer D may each preferably comprise a copolymer of a compound represented by the below-described formula (2) and a methacrylic monomer.
• X represents a halogen atom, alkylthio group, arylthio group, alkylsulfoxide group, arylsulfoxide group, benzyloxy group or alkylbenzyloxy group
• R represents a hydrogen atom or an n-valent ester residual group
• n stands for a number of from 1 to 4.
• the compound of the formula (2) is a compound having an eliminative group at its ⁇ -carbon, and induces addition-fragmentation chain transfer polymerization that a propagating radical at an end of an added monomer or a polymer obtained from the monomer attacks the unsaturated bond in the compound of the formula (2) to form a radical at the ⁇ -carbon of the compound of the formula (2), transfer of the radical causes elimination of the eliminative group (X), which is substituted on the methyl group at the ⁇ -position as a radical, and then, the thus-eliminated radical reacts to the monomer to form a polymer.
• an unsaturated bond derived from the compound of the formula (2) is formed at an end of the resultant polymer.
• a macromonomer with an unsaturated bond contained at an end thereof (the macromonomer that becomes “units A” in the present invention) is formed.
• the eliminative group (X) can be at least one atom or group selected from the group of halogen atoms such as fluorine atom, chlorine atom, bromine atom and iodine atom; alkylthio groups such as methylthio group, ethylthio group, butylthio group, t-butylthio group, octylthio group, laurylthio group, cyclohexylthio group, benzylthio group, hydroxyethylthio group and carboxyethylthio group, and arylthio groups such as phenylthio group, naphthylthio group, methylphenylthio group and ethylphenylthio group; alkylsulfoxide groups and phenylsulfoxide groups such as methylsulfoxide group, ethylsulfoxide group, trichloromethylsulfoxide group, tri
• the compound of the formula (2) can be obtained by a conventionally-known production process, and no particular limitation is imposed on its production process.
• a production process it can be obtained, for example, by causing formaldehyde to act on acrylic acid or its ester compound in the presence of a strong base such as diazabicyclo (2.2.2)octane or diazabicyclo (5.4.0)undecene to methylolate the ⁇ -carbon of the acryloyloxy group or reacting formaldehyde to triethyl phosphonoacetate to obtain an ⁇ -hydroxymethylacrylic acid or its ester compound, and then halogenating the hydroxyl group of the resultant product, for example, with phosphorus trichloride, phosphorus tribromide or the like.
• hydrogen bromide can be reacted to diethyl bis(hydroxymethyl)malonate to obtain its halide directly.
• an alkylthio group, arylthio group, alkylsulfoxide group or arylsulfoxide group can be introduced into the halide by reacting an alkyl thiol, aryl thiol, alkylsulfonic acid or arylsulfonic acid to the halide in the presence of a base such as triethylamine to conduct an interchange reaction with the halide.
• a benzyloxy group can be introduced into the halide by benzyletherifying the halide with benzyl alcohol or the like in the presence of potassium t-butoxide.
• acrylic acid or acrylate ester compound to be used upon introducing the eliminative group to the ⁇ -carbon one known to date can be used and no particular limitation is imposed thereon.
• Specific examples include acrylic acid; alkyl and cycloalkyl esters of acrylic acid, such as the methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, 2-ethylhexyl, lauryl, benzyl, cyclohexyl, 3,3,5-trimethylcyclohexyl, t-butylcyclohexyl, cyclodecyl and isobornyl esters of acrylic acid; (poly) alkylene glycol acrylates, their alkyl ethers, and their esterified products with dibasic acids such as phthalic acid; and amino-containing acrylate esters such as the dimethylaminoethyl, diethylaminoethyl and t-buty
• an ⁇ -substituted methylacrylic acid having two or more eliminative groups or an ester thereof can also be used. It can be obtained by using a compound containing two or more acryloyloxy groups, methylolating it in a similar manner as in the above, and then subjecting the methylolation product to halogenation, alkylthioation, alkylsulfoxidation or the like.
• acryloyloxy-containing polymers obtainable by esterifying, with acrylic acid, hydroxyl groups in polymers, such as hydroxyl-containing poly(meth)acrylates.
• hydroxyl-containing poly(meth)acrylates can be obtained by homopolymerizing ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbit, sorbitol, and their (poly)alkylene glycol derivatives; (poly) alkylene glycol derivatives such as bisphenol A, hydrogenated bisphenol A and bisphenol S; esters containing hydroxyl groups at both ends thereof, such as the ester of ethylene glycol and adipic acid; and hydroxyl-containing, radical polymerizable monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate, or by copolymerizing them with other monomers.
• the macromonomer means a monomer of high molecular weight, which is a polymer-type monomer having at an end thereof a group containing a polymerizable double bond.
• the radical polymerizable monomer to be polymerized with the compound of the formula (2) is specifically methacrylic acid or its ester in the present invention, because the use of a radical polymerizable monomer, for example, a vinyl monomer such as styrene, an acrylic monomer such as butyl acrylate or an amide monomer such as acryl amide in the polymerization with the compound of the formula (2) induces a radical polymerization reaction between its unsaturated bond and the unsaturated bond in the compound of the formula (2) so that the compound of the formula (2) is incorporated as a polymer component in the resulting polymer to make it difficult to obtain a polymer having the unsaturated bond in the unit of the formula (1) at an end thereof.
• a radical polymerizable monomer for example, a vinyl monomer such as styrene, an acrylic monomer such as butyl acrylate or an amide monomer such as acryl amide in the polymerization with the compound of the formula (2) induces a radical polymerization
• Methacrylic acid or its ester has low polymerizability with the unsaturated bond in the unit of the formula (1), and can undergo addition-fragmentation chain transfer polymerization to provide a macromonomer having the unsaturated bond in the unit of the formula (1) at an end thereof.
• methacrylic acid or its ester to be used one known to date can be used and no particular limitation is imposed thereon.
• Specific examples include methacrylic acid, methacryloyloxyethylsulfonic acid, methacryloyloxyethanephosphoric acid, and their esters; alkyl and cycloalkyl esters of methacrylic acid, such as the methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, 2-ethylhexyl, lauryl, benzyl, cyclohexyl, 3,3,5-trimethylcyclohexyl, t-butylcyclohexyl, cyclodecyl and isobonyl esters of methacrylic acid; esters of (poly)alkylene glycol methacrylates, their esterified products with dibasic acids such as phthalic acid, and their alkyl ethers; amino-
• the copolymer D of the present invention When the copolymer D of the present invention is used in an aqueous medium, it is preferred to incorporate monomer units, each of which contains an acid group capable of forming a salt upon neutralization, in the macromonomer such that the copolymer D is rendered hydrophilic and the acid value is controlled to from 50 to 300 mgKOH/g.
• the acid group capable of forming the salt upon neutralization a carboxyl group, sulfonic group or phosphoric group can be mentioned.
• Specific usable monomers include carboxyl-containing monomers obtainable by reacting a dibasic acid with methacrylic acid or (poly)alkylene glycol methacrylates into half esters; sulfonic-containing monomers such as methacryloyloxyethylsulfonic acid; and phosphoric-containing monomers such as methacryloyloxyethanephosphoric acid and its esters. These monomers can be used either singly or in combination.
• the side chains of the pigment dispersant obtained using the copolymer D of the present invention or the resulting resin dispersion must show sufficient hydrophilicity
• the acid value of the macromonomer to be introduced may be preferably from 50 to 300 mgKOH/g, more preferably from 100 to 250 mgKOH/g.
• An acid value smaller than 50 mgKOH/g requires the introduction of the macromonomer in a greater amount to provide the copolymer D with increased hydrophilicity, and in such a case, an inconvenience arises such that the macromonomer does not react for its polymerizability and remains in the polymerization system.
• the macromonomer can be introduced in a smaller amount in the copolymer D.
• the amount of the macromonomer in the copolymer D decreases so that the properties of the macromonomer may not be exhibited or the copolymer D may not show sufficient hydrophilicity.
• the copolymer D is provided with excessively high hydrophilicity so that a pigment dispersion prepared using the copolymer D may not be suited for the maintenance of stability or, when the copolymer D is incorporated in an article, the article may be provided with deteriorated waterproofness.
• a macromonomer By polymerizing the compound of the formula (2) and a methacrylic monomer with an azo initiator or peroxide initiator in accordance with conventionally-known solution polymerization, bulk polymerization, suspension polymerization or emulsion polymerization, a macromonomer can be obtained with groups represented by the formula (1).
• the macromonomer can be used as it is, or can be used after causing it to precipitate in a poor solvent or neutralizing it with an acid or alkali to precipitate it and then collecting it in the form of a solid.
• the macromonomer can be used in the form of a solid after collecting it by filtration in the case of suspension polymerization or in the form of a solid after conducting heating or salting out and collecting only the resin in the case of solution polymerization or emulsion polymerization.
• Solution polymerization can be conducted by a conventionally-known polymerization process in a conventionally-known liquid medium which can dissolve the compound of the formula (2) and the methacrylic monomer.
• the liquid medium include water; and as organic solvents, toluene, xylene, methyl ethyl ketone, ethyl acetate, ethanol, isopropanol, propylene glycol monoalkyl ethers, ethylene glycol monoalkyl ethers, propylene glycol, dimethylformamide, dimethylsulfoxide, methylene chloride, tetrahydrofuran, and hexane. They can be used either singly or in combination, and no particular limitation is imposed on the liquid medium.
• the copolymer D When the copolymer D is obtained in a water-soluble form, the copolymer D can be formed into an aqueous solution after its polymerization by neutralizing it with alkaline water while using a water-soluble organic solvent, for example, an alcohol solvent such as ethanol or isopropanol or a glycol solvent such as ethylene glycol monoalkyl ether, diethylene glycol monoalkyl ether or propylene glycol monomethyl ether.
• a water-soluble organic solvent for example, an alcohol solvent such as ethanol or isopropanol or a glycol solvent such as ethylene glycol monoalkyl ether, diethylene glycol monoalkyl ether or propylene glycol monomethyl ether.
• the molecular weight of the macromonomer may be from 500 to 100,000, preferably from 1,000 to 30,000, more preferably from 2,000 to 10,000 in terms of number average molecular weight (GPC, polystyrene calibration).
• the copolymer D of the present invention which is useful as a pigment dispersant or resin dispersion, can be obtained by copolymerizing the macromonomer, which is obtainable as described above, and the monomer for units B, optionally together with the other monomer for units C as needed.
• the reactivity of its end group is known to be relatively poor unlike the radical polymerizability of the unsaturated bond of a conventional (meth)acrylic monomer or vinyl monomer.
• radical polymerization with another monomer in the presence of this macromonomer is known to cause the binding of an end radical of a polymer of another monomer with the terminal double bond of the macromonomer so that up to two polymer chains can bind to one group of the formula (1).
• An aromatic vinyl monomer (the monomer for units B) is known to be particularly suited as the monomer to be copolymerized, and the present invention is characterized by the use of this monomer for units B as a comonomer. If a methacrylate monomer is employed without using the monomer for units B, addition-fragmentation chain transfer polymerization occurs again to terminal double bond groups, and therefore, the copolymer D of the present invention cannot be obtained.
• macromonomers each of which contains a (meth) acrylic group at an end thereof. They are each a polymer having at an end thereof a radical-polymerizable, unsaturated bond of a (meth) acrylic group and obtained by polymerizing a monomer with use of a chain transfer agent such as hydroxyethyl thiol or 2-mercaptoethylcarboxylic acid to obtain a polymer with a hydroxyl group or carboxyl group introduced to an end thereof, and reacting the resultant polymer with isocyanatoethyl (meth)acrylate or the like in the case of the hydroxyl group or reacting the resultant polymer with glycidyl methacrylate or the like in the case of the carboxyl group.
• a macromonomer When such a macromonomer is used, its terminal unsaturated bond is high in reactivity so that the macromonomer undergoes usual radical polymerization with another radical-polymerizable monomer to afford a
• the use of the macromonomer in a large amount may cause the macromonomer to remain as it is without polymerization in some instances, leading to the problem that it cannot be introduced in such a large amount.
• the percent introduction of the macromonomer is hence as low as 40 wt % or so.
• the macromonomer takes part in its entirety in the polymerization even if the macromonomer is used abundantly, leading to the finding that the macromonomer is very useful as a macromonomer to be introduced.
• the copolymer D according to the present invention can, therefore, be obtained from the macromonomer, the monomer for units B and the monomer for units C as needed.
• the macromonomer in the present invention is known to take part in the polymerization that as described above, the coexisting monomer undergoes polymerization to form a polymer, the terminal propagating radical of the polymer binds to the unsaturated bond in the formula (1), and therefore, up to two polymer chains bind. In the present invention, however, it is not absolutely necessary to have two polymer chains bound to the one unsaturated bond in the formula (1).
• the present invention is characterized in that in the copolymer D obtained by the polymerization of the macromonomer, the monomer for units B and another monomer for units C, the respective units exhibit their own functions.
• the binding of one polymer chain to the unsaturated bond of the macromonomer may result in a block copolymer, while the binding of two polymer chains to the unsaturated bond of the macromonomer may lead to a form that one macromonomer chain is grafted on a copolymer, specifically to the form of a T-shaped, branched copolymer D formed of one macromonomer chain, the monomer for units B and the monomer for units C.
• the copolymer D according to the present invention which has been obtained using a macromonomer having two or more groups of the formula (1), is a highly-branched, star-shaped copolymer.
• two polymer chains can further bind to each of the groups of the formula (1) as described above.
• the binding of such additional polymer chains is not absolutely needed.
• a macromonomer having three groups of the formula (1) for example, six chains of a polymer formed from the monomer for units B and another monomer for units C can bind. Even with four chains of such a polymer, a copolymer D of a branched structure according to the present invention can still be formed, and therefore, is also usable satisfactorily in the present invention.
• the amount of the macromonomer (units A) in the copolymer D of the branched structure according to the present invention is from 5 to 95 wt %, preferably from 20 to 80 wt % when the total of the macromonomer and the units B is assumed to be 100 wt %. If the amount of the macromonomer is smaller than 5 wt %, the properties of the macromonomer hardly appear on the copolymer D of the branched structure, and further, a polymer formed from a monomer for units B and/or another monomer for units C may exist without binding to the macromonomer.
• the amount of the macromonomer is greater than 95 wt %, on the other hand, the properties of the polymer formed from the monomer for units B and/or another monomer for units C hardly appear on the copolymer of the branched structure, and further, the macromonomer may remain as it is in the polymerization system without binding.
• a conventionally known monomer can be used as the monomer for units B in the present invention.
• a conventionally known monomer can be used.
• Specific examples include styrene, ⁇ -methylstyrene, vinyltoluene, vinylxylene, vinyldimethylbenzene, vinyltrimethylbenzene, vinylethylbenzene, vinylpyridine, vinylimidazole, vinylnaphthalene, chloromethylstyrene, methoxystyrene, dimethylaminomethylstyrene, hydroxymethylstyrene, styrenecarboxylic acid and its metal salts, and styrenesulfonic acid and its metal salts.
• Particularly preferred are styrene, ⁇ -methylstyrene, vinyltoluene, vinyldimethylbenzene, vinylethylbenzene, and vinylnaphthalene.
• the monomer for units B acts not only to control such polymerization as described above, but also to provide the copolymer D with higher compatibility with pigments, and, when the copolymer is used as a pigment dispersant, to provide the copolymer D with increased pigment adsorbability and good pigment microdispersibility.
• the units B are contained at from 95 to 5 wt % in the copolymer D. This amount of the units B may preferably be from 80 to 20 wt % for similar reasons as the above-described amount of the macromonomer.
• Another monomer for units C may also be used as needed in addition to the monomer for units B.
• the monomer for units C is needed to be a monomer that is radically polymerizable with the monomer for units B.
• a conventionally-known monomer can be used, and no particular limitation is imposed thereon.
• Illustrative are such (meth)acrylic acid monomers as described above; amide monomers such as (meth) acrylamide, (meth) acryldimethylamide and dimethylpropanesulfonic acid acrylamide; unsaturated-bond-containing dibasic acid monomers such as fumaric acid, crotonic acid, maleic acid and itaconic acid, and their aliphatic, alicyclic or aromatic half esters or diesters; and vinyl monomers such as vinyl acetate, propyl acetate, vinylpyrrolidone, vinyl chloride, vinylidene chloride, ethylene, propylene, phenylmaleimide and cyclohexylmaleimide. In the polymerization between the macromonomer and the monomer for units B, these monomers can provide the resulting copolymer D with modified properties.
• amide monomers such as (meth) acrylamide, (meth) acryldimethylamide and dimethylpropanesulfonic acid acrylamide
• the use of a functional-group-containing monomer for units C in the copolymer D can provide the pigment dispersant with increased adsorbability on a pigment to increase pigment dispersibility.
• the functional group can be one selected from the group consisting of nitrogen-containing heterocyclic groups such as carboxyl group, hydroxyl group, sulfonic group, phosphoric group, amino group, quaternary ammonium group, imidazolyl group, benzotriazolyl group and pyridyl group. Therefore, a conventionally-known monomer can be used, and no particular limitation is imposed thereon.
• the use of the above-described monomer for units C is not essential.
• the amount of the monomer for units C can be in a range of from about 5 to 200 parts by weight when the total of the macromonomer and the monomer for units B is assumed to be 100 parts by weight. No problem arises even if the monomer for units C is used in an amount smaller than the above-described range.
• the use of the monomer for units C in an amount greater than the above-described range may cause a polymerization reaction of the monomer for units C with the macromonomer, so that the structure of the present invention may not be obtained or the performances of the macromonomer and units B may not be exhibited to full extents.
• the molecular weight of the copolymer D according to the present invention may be in a range of from 1,000 to 100,000 in terms of number average molecular weight (GPC, polystyrene calibration).
• GPC number average molecular weight
• a number average molecular weight lower than 1,000 may provide the resulting pigment dispersion with poor dispersion stability.
• a resin dispersion is used as a coating formulation, such a low number average molecular weight provides the resulting coated article with poor durability.
• the copolymer D When the copolymer D is used as a pigment dispersant, a number average molecular weight higher than 100,000, on the other hand, provides the resulting pigment dispersion with unstability in terms of the dispersion of the pigment so that the pigment cannot be dispersed as microparticles.
• the macromonomer contained in the copolymer D may preferably have an acid value of from 50 to 300 mgKOH/g as described above, and the overall acid value of the copolymer D may be preferably from 50 to 250 mgKOH/g, more preferably from 60 to 200 mgKOH/g, including both the above-described acid value of the macromonomer units and the acid value of the units C copolymerized as needed and containing acid groups.
• an acid value of smaller than 50 mgKOH/g does not provide the copolymer D with sufficient hydrophilicity so that the copolymer D may not show water solubility or water dispersibility.
• An acid value of greater than 250 mgKOH/g provides the copolymer D with excessively high hydrophilicity so that the copolymer D is not suited as a pigment dispersant.
• the resulting article is provided with significantly deteriorated waterproofness.
• a hydrophilic monomer having a hydroxyl group, amino group or polyalkylene glycol chain, such as those described above, may also be used in combination.
• the copolymer D according to the present invention is significantly characterized in that as described above, it has the structure that the properties of the polymers formed of the macromonomer, units B and units Care independently retained, in other words, the respective units are different in properties.
• the copolymer D according to the present invention is significantly characterized in that the macromonomer and the polymer formed of the units B and units C are independent from each other in function such that the macromonomer is good in solvent solubility and the polymer is high in pigment compatibility and is insoluble in a liquid medium.
• the copolymer D can be obtained by directly adding the monomer for units B and the monomer for units C subsequent to the production of the macromonomer as described above, and then conducting solution polymerization.
• the copolymer D can be obtained by dissolving the macromonomer in a liquid medium capable of dissolving the macromonomer, adding the monomers, and then conducting solution polymerization.
• the copolymer D When it is desired to use the copolymer D as a pigment dispersant in aqueous systems, the copolymer D can be obtained as a pigment dispersant for aqueous systems by dissolving the acid-group-containing macromonomer in a liquid medium capable of dissolving it, adding the monomers, and subsequent to polymerization, neutralizing the acid groups with an alkaline substance to provide water compatibility.
• Alkaline substances usable for the neutralization include the hydroxides and carbonates of alkali metals and transition metals, ammonia, and amines.
• Illustrative are lithium hydroxide, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, ammonia, hydrazine, morpholine, N-methylmorpholine, trimethylamine, triethylamine, ethanolamine, diethanolamine, triethanolamine, aniline, 2,2,6,6-tetramethylpiperidine, 2,2,6,6-tetramethyl-4-piperidinol, 1,2,2,6,6-pentamethylpiperidine, 1,2,2,6,6-pentamethyl-4-piperidinol, and aminomethylpropanol. They can be used either singly or in combination.
• the copolymer D of the present invention which is useful as a pigment dispersant, is characterized in that its macromonomer has sufficient compatibility with a liquid medium as a dispersion medium for a pigment and is soluble in the liquid medium and also in that it has a structure that shows compatibility with the pigment.
• the liquid medium is an organic solvent
• aromatic rings originated from the monomer for units B and the above-described functional groups provide increased compatibility with the pigment to increase the pigment adsorbability
• the macromonomer increases the compatibility with the liquid medium. It is, therefore, possible to finely disperse the pigment, and hence to obtain a pigment dispersion having good storage stability.
• the above-described macromonomer which has been obtained by neutralizing the acid groups is high in hydrophilicity, and therefore, is dissolved in water, so that the copolymer D formed of the macromonomer, units B and units C is adsorbed on the pigment owing to its hydrophobic action or owing to the above-described functional-group-containing monomer copolymerized as needed. It is, therefore, possible to finely disperse the pigment, and hence to obtain a pigment dispersion having good storage stability.
• the macromonomer equipped with solubility acts to disperse or emulsify the copolymer D in the form of particles of from several nanometers to several micrometers, preferably from 20 nm to 1 ⁇ m, more preferably from 50 nm to 500 nm so that a resin dispersion is formed.
• the resin dispersion in the water-based liquid medium can be obtained by homopolymerizing or copolymerizing, as a water-soluble macromonomer, such an acid-group-containing monomer as described above, a hydroxyl-containing methacrylate ester monomer such as hydroxyethyl methacrylate, a methacrylate monomer of polyethylene glycol, a polyethylene glycol-polypropylene glycol random or block copolymer, or an alkyl ether or alkyl ether thereof, or the like.
• a water-soluble macromonomer such an acid-group-containing monomer as described above
• a hydroxyl-containing methacrylate ester monomer such as hydroxyethyl methacrylate
• a methacrylate monomer of polyethylene glycol a polyethylene glycol-polypropylene glycol random or block copolymer
• alkyl ether or alkyl ether thereof or the like.
• the resin dispersion in the water-based liquid medium can be obtained by polymerizing a monomer for units B and another monomer for units C with a conventionally-known initiator in the presence of a macromonomer obtained by neutralizing the acid group with the above-described alkaline substance.
• a resin dispersion which makes use of an organic solvent as a liquid medium, can be obtained by polymerizing a monomer for units B and another monomer for units C with a conventionally-known initiator in the presence of a macromonomer designed to be dissolved in the organic solvent such that the resulting copolymer D is not soluble in the organic solvent, although it is not necessary so because as examples of a macromonomer soluble in an organic solvent, a variety of macromonomers exists depending on organic solvents.
• a very stable resin dispersion can be afforded by obtaining a macromonomer from a long-chain alkyl methacrylate monomer such as 2-ethylhexyl methacrylate as a homopolymerization or copolymerization component in an aliphatic hydrocarbon solvent and then polymerizing styrene and vinyl acetate in the presence of macromonomer, because a copolymer of styrene and vinyl acetate is insoluble in the hydrocarbon solvent and hence, the dissolved macromonomer undergoes copolymerization to stabilize the copolymer D as particles.
• a macromonomer from a long-chain alkyl methacrylate monomer such as 2-ethylhexyl methacrylate as a homopolymerization or copolymerization component in an aliphatic hydrocarbon solvent
• polymerizing styrene and vinyl acetate in the presence of macromonomer, because a copolymer of s
• the proportions of the macromonomer, the monomer for units B and the monomer for units C are as described above, although the content of the macromonomer may preferably be 20 wt % or more of the whole monomers especially for the stabilization of the resin dispersion.
• the copolymer D according to the present invention can be used as a pigment dispersant or as a film-forming component of the resin dispersion type.
• a pigment and a liquid medium are mixed to disperse the pigment, and if necessary, classification is further conducted. As a result, a pigment dispersion can be obtained.
• pigments which can be prepared into pigment dispersions by using the copolymer D according to the present invention conventionally-known pigments are all usable.
• Illustrative organic pigments include phthalocyanine pigments, azo pigments, azomethineazo pigments, azomethine pigments, anthraquinone pigments, perinone/perylene pigments, indigo/thioindigo pigments, dioxazine pigments, quinacridone pigments, isoindoline pigments, isoindolinone pigments, and carbon black pigment.
• illustrative inorganic pigments include extender pigments, titanium oxide pigments, iron oxide pigments, and spinnel pigments.
• a conventionally-known pigment can also be prepared into a pigment dispersion by making combined use of a pigment derivative having a structure similar to the conventionally-known pigment as needed and then conducting dispersion processing.
• a pigment may desirably be chosen based on the application purpose in view of its kind, particle size and processing. Except for cases in which the pigment dispersion requires hiding power, a microparticulate, organic pigment is desired. Especially when transparency is desired, it is desirous to eliminate pigment particles of 0.5 ⁇ m and greater such that the average particle size is controlled to 0.15 ⁇ m or smaller.
• a liquid medium and a pigment there are two methods.
• the pigment is treated beforehand with the pigment dispersant (the copolymer D), and subsequent to incorporation of various additives as needed, the resultant mixture is dispersed in the liquid medium.
• the untreated pigment, the pigment dispersant, the liquid medium, and if necessary, various additives are mixed, and the resultant mixture is subjected to dispersion processing in a disperser.
• the pigment, dispersant and liquid medium are mixed, and if necessary, the resultant mixture is subjected to dispersion processing in a disperser.
• An acid such as sulfuric acid, hydrochloric acid or acetic acid is added to acid out the pigment or the pigment is caused to precipitate in a poor solvent, so that pigment particles are coated with the pigment dispersant.
• the coated pigment particles are then subjected to filtration, water washing, drying and grinding to obtain the treated pigment.
• the treated pigment is then poured into an alkali-containing water so that the treated pigment is neutralized and dissolved.
• the treated pigment is poured into an organic solvent and is dissolved. If necessary, dispersion processing is performed in a disperser. In the above-described manner, a pigment dispersion can be obtained.
• the pigment dispersant of the present invention the pigment and, if necessary, various additives are added, and subsequent to premixing as needed, dispersion is performed in the disperser to obtain a pigment dispersion.
• a conventionally-known disperser can be used. Usable examples include a kneader, an attritor, a ball mill, a sand mill or horizontal medium disperser making use of glass or zircon, and a colloidal mill.
• the concentration of the pigment in the pigment dispersion may be preferably from 0.5 to 50 wt %, more preferably from 0.5 to 30 wt %.
• the content of the dispersant in the pigment dispersion may desirably be from 5 to 500 parts by weight per 100 parts by weight of the pigment.
• the viscosity of the pigment dispersion may be preferably from 1 to 50 mPas, more preferably from 2 to 30 mPas. It is particularly important to note that the use of the pigment dispersant according to the present invention provides the resulting pigment dispersion with excellent viscosity stability over time.
• various additives can also be added in addition to the pigment, dispersant and liquid medium.
• durability or fastness improvers such as ultraviolet absorbers and antioxidants, anti-settling agents, release agents or releasability improvers, fragrances, antimicrobial agents, antimolds, plasticizers, anti-drying agents and the like can be used.
• dispersion aids, pigment treatments, dyes and the like can also be added.
• the resulting pigment dispersion can be used as it is, but from the standpoint of providing the pigment dispersion with enhanced reliability, it is preferred to remove coarse particles, which may exist a little, by a centrifuge, ultracentrifuge or filter.
• pigment dispersions can be obtained.
• These pigment dispersions can be used as colorants in conventionally-known paints, inks, coating compositions, stationeries and toners. Described specifically, they can be used as colorants in water-based paints, oil-based paints, gravure inks, water-based flexographic inks, inkjet inks, inks for stationeries, inks for writing utensils, coating compositions, colors for color filters, wet toners and the like.
• the amount of the pigment dispersant to be added varies depending on the concentration of the pigment and cannot be specified in a wholesale manner.
• the pigment dispersant can be used as much as needed depending on the required coloring density.
• the resin dispersion with the copolymer D of the present invention contained therein can be used by adding it to paints, inks, coating compositions, stationeries and toners. It can be used as film-forming components or lustering or matting additives in conventionally-known paints, inks, coating compositions and stationeries, more specifically and for example, paints, oil paint varnishes for offset inks, binders for gravure inks, inkjet inks, inks for stationeries, coating compositions, alkali-strippable resists for color filters, wet toners and the like, and can impart high adhesion or high glossiness to films.
• the resulting film is provided with excellent waterproofness because it does not contain any surfactant as an emulsifier.
• the amount of the resin dispersion to be added for each application cannot be specified in a wholesale manner, but may be preferably from 3 to 50 wt %, more preferably from 5 to 30 wt % of the whole amount.
• the pigment dispersion which is obtained by using the pigment dispersant of the present invention, may also contain colorants conventionally known for the above-described respective applications as needed, and therefore, can be used in combination with conventionally-known pigments, dyes, colored polymer beads, microcapsulated colors, and the like.
• colorants conventionally known for the above-described respective applications as needed, and therefore, can be used in combination with conventionally-known pigments, dyes, colored polymer beads, microcapsulated colors, and the like.
• a conventionally-known crosslinking agent can be additionally used to provide the resulting films with improved various durability, waterproofness, solvent resistance and the like.
• a crosslinking agent include, but are not limited specifically to, isocyanate crosslinking agents, carbodiimide crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, melamine crosslinking agents, oxazoline crosslinking agents, and acid anhydride crosslinking agents.
• the crosslinking agent can be used in an amount preferably of from 1 to 50 wt.
• % more preferably from 3 to 20 wt. %, still more preferably from 5 to 10 wt. % in terms of solid.
• defoaming agents for the above-described applications, it is also possible to use, as an additive or additives, one or more of conventionally-known defoaming agents, preservatives, leveling agents, thickeners, moisture-retaining agents, plasticizers, antioxidants, ultraviolet absorbers, light stabilizers and the like.
• dimethylsulfoxide 500 parts
• water 170 parts
• ethyl acrylate 200 parts
• paraformaldehyde purity: 80%, 72.5 parts
• diazabicyclo 2.2.2 octane
• the extract was dried over anhydrous magnesium sulfate. After the thus-dried extract was concentrated in an evaporator, the concentrate was subjected to distillation under reduced pressure. Ethyl 2-(hydroxymethyl)acrylate was obtained (yield: 193 parts).
• the reaction product was identified to be the target compound by IR and NMR, and its purity was determined to be 98.7% by GC.
• the reaction mixture was then washed twice with a 0.5% aqueous solution of sodium hydroxide (200 parts, each), and was washed further with saturated NaCl solution (200 parts). Drying, concentration and reduced-pressure distillation were then conducted in a similar manner as described above. Ethyl 2-(bromomethyl) acrylate was obtained (yield: 48 parts).
• the reaction product was identified to be the target compound by IR and NMR, and its purity was determined to be 99.1% by GC. This compound will hereinafter be referred to as “the compound 1 of the formula (2)”.
• dimethylsulfoxide 100 parts
• water 170 parts
• dipropylene glycol diacrylate 24.2 parts
• paraformaldehyde purity: 80%, 3.75 parts
• diazabicyclo 2.2.2)octane
• the resulting resin solution will hereinafter be referred to as “the macromonomer 1”.
• the number average molecular weight was found to be 4,800 by GPC. There was no smell of residual monomer. Its solid content was determined to be 50.3%. Substantially all the monomers were, therefore, confirmed to be polymerized. Further, the acid value of the macromonomer was 195.7 mgKOH/g.
• the macromonomer 5 was caused to precipitate, and the resulting solid macromonomer will hereinafter be referred to as “the macromonomer 6”.
• the resulting resin solution will hereinafter be referred to as “the comparative polymer 1”, which had been obtained without using any compound of the formula (2) useful in the present invention and contained no ⁇ -substituted methyl acrylate ester groups. Its number average molecular weight was found to be 4,400 by GPC. A portion of the resin solution was caused to precipitate in water, and the thus-precipitated resin will hereinafter be referred to as “the comparative polymer 2”.
• the resulting resin solution will hereinafter be referred to as “the comparative polymer 3”, which had been obtained without using any compound of the formula (2) useful in the present invention, contained no ⁇ -substituted methyl acrylate ester groups and contained methacrylic groups at the ends. Its number average molecular weight was found to be 4,600 by GPC. A portion of the resin solution was caused to precipitate in methanol/water, and the thus-precipitated resin was measured by NMR. As a result, it was possible to confirm unsaturated bonds at 5.6 and 6.1 ppm, respectively.
• the weight ratio of the macromonomer to the monomers was 40/60, and the acid value was 78.8 mgKOH/g. Its molecular weight was measured. In the visible range, the molecular weight distribution peak ascribable to the macromonomer 1 substantially disappeared, but a single peak ascribable to a still higher molecular weight appeared. In the ultraviolet range (measurement wavelength: 254 nm), on the other hand, a similar molecular weight distribution peak as that available in the visible range appeared, although a peak ascribable to ⁇ -substituted methyl acrylate residual groups appeared extremely slightly as the molecular weight distribution peak of the macromonomer 1.
• the pigment dispersant 1 When a portion of the pigment dispersant 1 was diluted 10-fold with water, a pale, slightly-turbid, clear, aqueous solution was also obtained.
• this comparative example indicates that the comparative polymer 1 reacted with neither styrene nor 2-hydroxyethyl methacrylate and was in the form of a mixture. It is, therefore, indicated that, in each polymer of the present invention which is formed of the macromonomer of Example 1, said macromonomer containing ⁇ -substituted methyl acrylate residual groups, and other monomers, the macromonomer has been incorporated in the polymer.
• the macromonomer 3 or 4 (solution) was charged into a similar reactor as in Polymerization Example 1, followed by heating to 80° C.
• styrene and 2-hydroxyethyl methacrylate were combined at 2/1, and “PERBUTYL O” was mixed at a concentration of 2% based on the monomers to prepare a monomer solution.
• the monomer solution was added dropwise over 1 hour at the solid content ratio (X/Y) shown in Table 3. Subsequently, polymerization was conducted at the same temperature for 6 hours.
• pigment dispersant 2 to pigment dispersant 4 showed similar GPC peaks as the pigment dispersant 1, and were confirmed to have higher molecular weights commensurate with the used amounts of the monomers.
• the foregoing suggests that these pigment dispersants 2 to 4 each have a block or T-shaped branched structure.
• the polymer obtained as described above was a pigment dispersant, in which the weight ratio of the macromonomer to the monomers was 50/50 and the acid value was 98.5 mgKOH/g.
• the weight ratio of the macromonomer to the monomers was 50/50 and the acid value was 98.5 mgKOH/g.
• peak profiles or the like were similar to those described above and the number average molecular weight was 5,500.
• This polymer will hereinafter be referred to as “the pigment dispersant 5”.
• the pigment dispersant 5 When a portion of the pigment dispersant 5 was diluted 10-fold with water, a pale, slightly-turbid, clear, aqueous solution was also obtained.
• the macromonomer 12 was a highly-branched pigment dispersant, in which the weight ratio of the macromonomer to the monomers was 50/50 and the acid value was 98.5 mgKOH/g. As the macromonomer 12 does not gel, it is indicated that macromonomer 12 is useful in the present invention and can provide a branched pigment dispersant. As a result of measurement of its molecular weight, peak profiles or the like were similar to those described above, and the number average molecular weight was 12,300.
• the pigment dispersant 6 When a portion of the pigment dispersant 6 was diluted 10-fold with water, a pale, slightly-turbid, clear, aqueous solution was also obtained.
• the resin dispersion 1 This dispersion will hereinafter be referred to as “the resin dispersion 1”.
• the above-described procedure was repeated likewise except for the use of the macromonomer 6 (solid) in place of the macromonomer 2.
• an emulsion-like dispersion was obtained with a color whiter than the resin dispersion 1.
• the peak profile contained a single peak, and the number average molecular weight was found to be 32,500.
• This dispersion will hereinafter be referred to as “the resin dispersion 2”.
• Example 4 Using a similar reactor as in Polymerization Example 1, synthesis was conducted in a similar manner as in Example 4 except for the use of the comparative polymer 2 in place of the macromonomer 2. As in Example 4, the reaction system became clouded so that a pale semi-clear dispersion was obtained. As a result of measurement of the polymerization product for its molecular weight, a combined peak ascribable to the comparative polymer 2 and a polymer of styrene and butyl acrylate was observed. The number average molecular weight was 31,000. This polymerization product will hereinafter be referred to as “the comparative polymer 6”.
• the resin dispersions 1 and 2 and the comparative polymer 6 were separately diluted 2-fold with water, and to the resulting dilutions, isopropyl alcohol (IPA) was added little by little under stirring, respectively.
• IPA isopropyl alcohol
• the resin began progressively precipitate, thereby indicating that the resin had poor solvent dilutability.
• the resin did not undergo precipitation and remained stable even when diluted with IPA.
• the comparative polymer 2 which acted as a protective colloid for the comparative polymer 6 was not bound to the polymer of styrene and butyl acrylate and was in a dissolved state in water, and upon addition of IPA, was caused to precipitate.
• each pigment dispersant was obtained as will be described hereinafter.
• additional solvent was added to the corresponding one of the macromonomers 7 to 10 and 13 (solutions) to give a solid content of 40%.
• PERBUTYL O 2% based on the monomers
• polymerization was conducted at 78° C. or 90° C. for a predetermined time.
• oily pigment dispersants 7, 8, 9, 10 and 11 were obtained.
• Table 4 It is to be noted that each X/Y in the table indicates the weight ratio of the macromonomer to the monomers.
• aqueous dispersion having a resin content of 300.
• the aqueous dispersion 150 parts
• ethylene glycol 40 parts
• purified water 160 parts
• a black pigment “Raven 2500 Powder (U)” product of Columbia Carbon Co., Ltd.; 150 parts
• purified water 250 parts was added to the mill base to afford a pigment dispersion of 20% pigment content.
• the inkjet inks obtained as described above were separately filled in ink cartridges, and by an inkjet printer, solid printing was performed on glossy inkjet paper, “PHOTOLIKE QP” (product of KONICA CORPORATION).
• PHYLIKE QP product of KONICA CORPORATION
• the pigment dispersant 1 was diluted into a 40% solution with water. To the solution (50 parts), morpholine (30 parts), ethylene glycol (50 parts), disodium ethylenediaminetetraacetate (30 parts) and a phthalocyanine pigment paste (265 parts; pigment content: 90 parts) were added. The resulting mixture was dispersed for 3 hours in a sand mill. Water (308 parts), ethylene glycol (131 parts), glycerin (36 parts) and thiourea (100 parts) were then added to lower the concentration of the pigment to 9%. The resulting mixture was then dispersed for 10 minutes to afford an aqueous pigment dispersion of a blue color.
• the dispersion was then processed by an ultracentrifuge to remove undispersed coarse particles, thereby obtaining an aqueous pigment dispersion having a pigment content of 8.7%, a viscosity of 4.3 mPas and an average particle size of 98 nm.
• the dispersion was filled in a plastic-made felt-tip pen which was equipped with a felt core and a pen point made by molding of plastics, and was then tested.
• Using the felt-tip pen characters were written on a polyethylene-made film. Smooth and clear writing was feasible without ink repellency while exhibiting sufficient hiding power and large tinting power.
• the written characters were immersed in water, but underwent neither running nor separation.
• the written film was subjected to a light fastness test for 100 hours and 500 hours under a fadeometer. As a result, no particular change was observed so that good light fastness was demonstrated. Further, the pigment dispersion was left over for 1 month in a constant-temperature chamber controlled at 50° C. to perform a storage stability test.
• the pigment dispersion was, therefore, found to have very good storage stability. Similar advantageous effects were also observed when the pigment dispersants 2, 3, 4 and 5 were individually used in place of the pigment dispersant 1.
• the pigment dispersant 4 400 parts, water (300 parts) and cyanine blue (300 parts) were charged in a ceramic ball mill, and then dispersed for 24 hours to afford a pigment dispersion for water-based paints.
• “WATERSOL S-126” 100 parts
• “WATERSOL S-695” 5 parts
• “WATERSOL S-683IM” 5 parts
• water (100 parts) were then added, followed by stirring.
• the above-described dispersion (30 parts) was added further, and the thus-obtained mixture was stirred to obtain a paint 1.
• the paint 1 was applied onto an aluminum plate and baked at 140° C. for 20 minutes. As a result, a beautiful, transparent, blue coating was formed.
• the painted plate was immersed for 30 minutes in boiling water, but its coating did not develop whitening, blistering or separation. The color development and gloss of the coating were good. Similar advantageous effects were also obtained when the pigment dispersions 3 and 5 were individually used in place of the pigment dispersion 4.
• a white pigment base color was prepared by kneading and dispersing twice in a sand mill a mixture consisting of titanium oxide white pigment (40 parts), a styrene-monobutyl maleate (40:60) copolymer (average molecular weight: approx. 3,500, 10 parts), isopropyl alcohol (10 parts), water (38.5 parts), the pigment dispersant 3 (1 part) and a silicone-based defoaming agent (0.5 part).
• the resin dispersion 1 solid content: 40%; 30 parts
• fine particulate silicic anhydride 0.5 part
• polyethylene wax 0.5 part
• a silicone-based defoaming agent 0.1 part
• an oxazoline crosslinking agent solid content: 30%; 3 parts
• water 8.9 parts
• an acrylic resin varnish (which had been obtained by copolymerizing benzyl methacrylate, methacrylic acid, 2-hydroxyethyl methacrylate at a molar ratio of 70/15/15; molecular weight: 12,000, acid value: 100 mgKOH/g, solid content: 40%) (50 parts); and as color filter pigments, PR (C.I. Pigment Red) 254, PG (C.I. Pigment Green) 36, PY(C.I. Pigment Yellow) 139, PY150, PB (C.I. Pigment Blue 15:6 and PV (C.I. Pigment Violet) 23. Base colors of respective colors for color resists were each prepared as will be described hereinafter.
• pigment dispersant 8 (11.5 parts) and a solvent (propylene glycol monomethyl ether acetate) (hereinafter abbreviated as “PMA”) (25 parts) were combined. Subsequent to premixing, they were dispersed in a horizontal bead mill. The thus-obtained pigment dispersions of the respective colors were measured to determine the average particle sizes of their pigments. As a result, it was found that the average particle sizes approximately ranged from 25 to 50 nm and the finely-divided pigments were sufficiently microdispersed. During storage, viscosity variations were within ⁇ 5% even when left over at 45° C. for 1 week.
• the pigment dispersant according to the present invention therefore, showed good pigment dispersibility.
• To fabricate an RGB color filter photosensitive pigment dispersions of R (red), G (green) and B (blue) colors were prepared in accordance with the formulas shown below in Table 6.
• Photosensitive pigment dispersions Formula (parts) Red Green Blue Red base color 100 — — Green base color — 100 — Blue base color — — 100 Acrylic resin varnish 50 50 50 Trimethylolpropane triacrylate 10 10 10 2-Hydroxy-2-methylpropiophenone 2 2 2 2,2-Diethoxyacetophenone 1 1 1 PMA 37 37 37 Total 200 200 200
• a glass substrate which had been subjected to treatment with a silane coupling agent was placed on a spin coater.
• the photosensitive pigment dispersion of R color for the color filter was spin-coated under conditions of firstly 300 rpm and 5 seconds and then 1,200 rpm and 5 seconds.
• Prebaking was then conducted at 80° C. for 10 minutes, a photomask with a mosaic pattern defined therein was brought into close contact with the resultant prebaked film, and by using an ultra-high pressure mercury vapor lamp, exposure was then conducted at a light quantity of 100 mJ/cm 2 .
• Development and washing were then conducted with a dedicated developer and a dedicated rinse to form a red mosaic pattern on the glass substrate.
• the thus-obtained color filter had superb spectral curve characteristics, and was excellent in fastness such as light fastness and heat resistance and also in light transmittance characteristics, and exhibited excellent properties as a color filter for a liquid-crystal color display. Similar high pigment dispersibility was also exhibited when the pigments 9 to 11 were used likewise.
• the pigment dispersant 8 (5 parts) was added to and dissolved in “ISOPAR H” (40 parts) which is an aliphatic hydrocarbon solvent. To the solution, a phthalocyanine blue pigment (10 parts) were added. After addition of glass beads, the mixture was shaken for 20 hours on a paint shaker to effect dispersion. The resin dispersion 3 (53.3 parts) was then added, followed by mixing under stirring to prepare a thick coloring solution of a blue color. The thick coloring solution (30 parts) was added to and dispersed in “ISOPAR G” (970 parts) to obtain a wet electrophotographic developer of a cyan color.
• ISOOPAR H 40 parts
• a phthalocyanine blue pigment 10 parts
• the resin dispersion 3 (53.3 parts) was then added, followed by mixing under stirring to prepare a thick coloring solution of a blue color.
• the thick coloring solution (30 parts) was added to and dispersed in “ISOPAR G” (970 parts) to obtain a wet electrophotographic developer of a cyan color
• the thick coloring solution and wet electrophotographic developer obtained as described above were excellent in dispersion stability, and even in diluted forms, the pigment did not precipitate much and moreover, it was possible to easily redisperse the precipitated small portions of the pigment.
• Using the wet electrophotographic developer of the cyan color obtained as described above copying was performed by a wet electrophotographic copying machine. As a result, cyan copy images were obtained with high image density and sharpness without much bleeding or scumming. Those images also showed excellent durability in various physical properties such as light fastness.
• the dispersion of a pigment with the copolymer of the present invention as a pigment dispersant makes it possible to obtain a highly-microdispersed pigment dispersion that can bring about very good dispersing effects and can also provide a resulting dispersion with excellent storage stability.
• the use of the copolymer of the present invention for the formation of a film can provide the resulting film with good properties.

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